The tracks on vehicles such as tanks need to be properly tensioned in order to operate most effectively and operate without excess maintenance. Track tension is typically controlled by moving a sprocket or idler wheel that engages the track, whereby the track is stretched or allowed to contract. A conventional mechanism for moving the sprocket or idler wheel is a track tensioner comprising a grease-filled cylinder. A piston in the cylinder moves as grease is added or removed through a fitting. The piston""s motion is transferred to the sprocket or idler wheel. One disadvantage with such a track tensioner is that a grease gun and grease must be at hand whenever the track needs tension adjustment. Also, such a track tensioner requires that personnel be outside the vehicle to use it. This is a problem, for example, when the vehicle is a tank in the forward area of an active combat zone. In addition, when the vehicle leaves one kind of terrain and enters another, it is often not practical to adjust track tension to a level preferred for the new terrain. Consequently, track tension is often set at the highest level that the vehicle might need, and this level is maintained even on terrain that does not require it. The unnecessary periods of high tension unduly accelerate track wear.
We address the foregoing concerns with our track tensioner, which is dynamic in that it adjusts tension of a moving track during vehicle travel. Our tensioner has a power screw that moves the vehicle""s sprocket or idler wheel to tighten or loosen the track. Connected to the power screw rod is a shock absorber comprising a cylinder closed at one end by a piston to contain a compressible fluid, the shock absorber moderating spikes in track tension. The power screw acts automatically to equalize actual track tension with desired track tension. Actual tension is determined by measuring fluid pressure in the cylinder whereas desired tension is selected by a person in the vehicle via a control circuit.